MULTISCALE SEGMENTATION - University of Pennsylvaniajshi/papers/MULTISCALE... · Florence Blorence...
Transcript of MULTISCALE SEGMENTATION - University of Pennsylvaniajshi/papers/MULTISCALE... · Florence Blorence...
-
MULTISCALEMULTISCALESEGMENTATIONSEGMENTATION
Florence BFlorence BENEZIT , Jianbo SHI, 2004ENEZIT , Jianbo SHI, 2004
-
IntroductionIntroduction
-
Graph Based Object SegmentationGraph Based Object Segmentation
Wij
Wiji
j
V: graph nodesE: edges connection nodes
Image = { pixels }Pixel similarity
Segmentation = Graph partition
-
Pixel Affinity graphPixel Affinity graph
-
Normalized Cut As Generalized Eigenvalue problemNormalized Cut As Generalized Eigenvalue problem
y2i iA
y2ii
A
Program PNCX:
Relaxed to program PNCZ:
-
How big connection radius?How big connection radius?
-
BAD AND GOODBAD AND GOODEIGENVECTORSEIGENVECTORS
-
ACCURACY VERSUSACCURACY VERSUSCOMPUTATION TIMECOMPUTATION TIME
-
MULTISCALEMULTISCALEAFFINITY MATRIXAFFINITY MATRIX
AND LAYERAND LAYERCONSTRAINTSCONSTRAINTS
-
Long range connectionsLong range connections
-
Statistics of W on natural imagesStatistics of W on natural images
-
MultiscaleMultiscale graph decomposition graph decomposition
-
Multi-Multi-scalescale graph decomposition graph decomposition
Original graph weight:O(N^2)
Multi-scale graph weights:O(N)
-
MULTISCALE MATRIXMULTISCALE MATRIX
-
AVERAGE MATRIXAVERAGE MATRIX
0001/9
1/9
1/9
0000001/9
1/9
1/9
0000001/9
1/9
1/9
0
-
AVERAGE MATRIXAVERAGE MATRIX
-
Con-current partitioning of Multi-Con-current partitioning of Multi-scalescale graph graph
-
MULTISCALE REPRESENTATIONMULTISCALE REPRESENTATIONAND CONSTRAINTSAND CONSTRAINTS
-
PROBLEMPROBLEM
-
MAXIMIZING ENERGYMAXIMIZING ENERGY
-
Cross scale constraintsCross scale constraints
-
RELAXED PROBLEMRELAXED PROBLEM
-
Can be done in O(N) operations.
-
Computational speed upComputational speed up
-
RESULTSRESULTS
-
EXAMPLESEXAMPLES
-
EXAMPLESEXAMPLES
-
EXAMPLESEXAMPLES